Airbags for motor vehicles have become ubiquitous in passenger vehicles. These airbags are installed at strategic points in the passenger compartment of a vehicle and, in the event of a collision, are rapidly inflated with gas so that they act as an energy absorbing barrier between the vehicle occupant and an interior surface of the passenger compartment (e.g., steering wheel, dashboard, or windows). For example, side curtain airbags typically are installed within one or more of the pillars of the vehicle so that they provide protection during roll-over or side impact collisions. With the advent of such airbags, manufacturers began coating the airbag fabric to modify the gas permeability of the fabric, enabling the airbags manufactured from the fabric to stay inflated for longer periods of time and provided the needed protection during the collision event.
There are many types of coating compositions used to produce such coated fabrics, but one class of coating composition that is becoming quite popular in the airbag industry is based on silicone elastomers. Silicone elastomers provide a great degree of flexibility in modifying the gas permeability of the fabric. Silicone elastomers also provide appreciable heat protection, which is beneficial given the high amount of heat to which the airbag can be exposed during its life in the automobile and the heat that is produced by the gas generator when the airbag is deployed. Despite these benefits, silicone elastomers themselves tend to be very weak. Therefore, they are frequently reinforced with fillers in order to produce a coating having the desired degree of tensile strength. The use of such reinforcing fillers is not without difficulties. These fillers often interact with the raw materials used to form the silicone elastomer, which can result in creep hardening as the filler and components are mixed or bin ageing as the mixed components are stored for later use. If unchecked, these effects can limit the utility of silicone elastomer-based coating compositions. These problems can be addressed to some degree using additional additives, but this complicates the compounding and increases the cost of the coating composition.
In view of the foregoing, it can be seen that a need remains for improved silicone elastomer-based coating compositions and coated airbag fabrics that can meet the demanding needs of the automotive airbag industry while addressing some of the problems inherent in current coating compositions and coated fabrics. Applicants believe that the coating composition and coated airbag described in the present application meet this need.